Jotaro is introduced as a rough, violent delinquent, but he has a gentle heart and is loyal to those he likes. He is highly perceptive, intelligent and quick-witted while keeping a perpetually cool, slightly neutral or disinterested attitude. He has a habit of muttering "Good grief…” to himself to express annoyance toward the ordeals and other events that happen close to him, to the point it has become his signature catchphrase.